1. Peel apples, cut into thirds, remove the core, and squeeze lemon juice over them.
2. Pour sugar into an ovenproof pan (this will go into the oven, so make sure there are no plastic handles). Place over medium heat and cook without stirring until the sugar starts to liquefy. At this point, you can start to slowly stir the sugar (do not mix vigorously) until the sugar is completely melted and starts to darken. Watch the liquefied sugar closely as it quickly goes from amber color to burnt sugar.
3. As soon as the sugar is a deep caramel color, about one to two minutes after it is fully liquid, remove from heat and add the butter or butter substitute. Whisk until well combined. Return pan to heat. Add in apples and cook on medium/high heat.
4. As the apples heat, they will release water and the caramel will become very liquidy. Gently stir the apples to cook evenly and fully coat with the caramel, until the liquid starts to evaporate and the caramel thickens. You want the apples to start to soften but not to turn to mush.
5. Remove pan from heat. Using tongs, arrange the apple slices in a circle around the inside of the pan, allowing them to overlap, as they will shrink more while baking.
6. While the apples cool slightly, preheat oven to 400 degrees Fahrenheit (200 degrees Celsius).
7. Roll out dough into a circle slightly larger than your pan. Place over the apples in the pan, tucking the edges into the pan.
8. Place the pan on a baking sheet to catch any drips and bake for 25–30 minutes, until dough is nicely browned.
9. Remove from oven and run a knife around the edge of the pan to loosen the pie. Allow to cool for at least 30 minutes. (This will allow the caramel to thicken a bit and seep into the apples.)
10. To serve, top the pan with a plate slightly larger than it and flip quickly. Slice the tart and serve warm with ice cream.